Slab-on-grade, basement, crawlspace, and raised pier are the four types of foundation approaches widely used in building construction. The basement, crawlspace and pier approaches all serve to elevate the first floor of the structure to an elevation that is at- or above-grade. In these cases, the insulation boundary is often located at the underside of the floor system. Since this under-floor insulation is at- or above-grade it is protected from water intrusion, and moisture is not a significant concern. Locating the thermal boundary at the floor deck also significantly reduces the volume of space that needs to be conditioned, requiring less energy overall to heat and cool the house. Therefore, insulated floors exist, with the predominant insulation material being fiberglass batts applied in the cavity between floor joists at the job site.
Such insulated floor structures are not, however, without drawbacks. First, installation with fiberglass batts between floor joists at the jobsite is very labor intensive. Second, fiberglass batt offers no air or vapor barrier layer, thus limiting building designs. Third, fiberglass batt has no inherent rigidity and can sag away from the subfloor over time, such sagging also leading to compression of the fiberglass batt, which results in a loss of thermal insulation performance (“R-value”). Finally, fiberglass batting offers no structural rigidity to enhance the structural performance of the floor structure.
As a result, it would be desirable to provide insulated floor structures that are fabricated away from the job site, are constructed so that the insulation is and will remain in contact with the subfloor, will not exhibit a deterioration in R-value over time, will contribute to the structural performance, including rollover strength, of the floor system, and is air and vapor impermeable to reduce the likelihood for condensation of water vapor across the temperature differential of the thermal envelope.
The present invention was made in view of the foregoing.